Engine starting mechanism



y 1944- R. M. NARDONE ENGINE STARTING MECHANISM Original Filed Oct. 22, 1940 Patenteci May 2, 1944 ENGINE STARTING MECHANISM Romeo M. Nardone, Westwood, N. J., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Original application October 22, 1940, Serial No. 362,272. Divided and this application April 20, 1942, Serial No. 439.761

2 Claims. (Cl. 74-305) This invention relates to engine starting mechanism, and particularly to the parts which function to facilitate or produce engine engaging movement of the member which couples the engine starter to the engine to be started.

An object of the invention is to provide an engine starter involving improvements in the starter structure; as, for example, in the structure which controls engagement of the starter with the engine.

A further object is to provide an engagement controlling mechanism, for an engine starter, characterized by improvements which reduce the number of parts requiring separate assembly and adjustment.

While the invention is shown in the accompanying drawing as applied to a starter having torque transmitting mechanism of the type shown in Lansing Patent No. 1,962,397, it is not limited to such an application, nor are there any limitations as to the physical appearance of the elements in which the invention may be embodied, except in so far as the appended claims uniformly recite such limitations. The drawing, therefore, merely illustrates the currently preferred mode of putting the invention 'into use; said drawing including:

Fig. 1, which is a central sectional view of a starter to which the invention is applicable;

Fig. 2, which is a perspective view of the screw element of the motion translating mechanism of Fig. 1;

Fig. 3 is a sectional view on line 33 of Fig. 2;

Fig. 4 is an end view of Fig. 2;

Fig. 5, which is a sectional view of the cooperating shell, or nut, element of the motion translating mechanism;

Fig. 6 is an end view of Fig. 5.

The starter, as illustrated in the drawing, includes a housing constituted by an inner section 3, an intermediate section 4, an outer section 5, and a plurality of screws 8 for detachably connecting said sections. The inner section 3 is provided with a flange l to receive bolts 8 for secu ng the starter to the crankcase of an engine, a portion of the latter being indicated at 9. Secured to the section 4 are the field coils of an electric motor l having an armature shaft ll whose outer end is received .in bearings l2 and whose inner endis received in a sleeve hearing l3 which is supported in thetransverse wall ll of a barrel I that is rotatably received in housing section 3. Adjacent the reduced portion of the armature shaftthere is formed a pinion it that meshes with a planetary gear set which operates to drivably connect armature shaft II with the barrel I, to rotate the latter in synchronism with rotation of the motor armature, but at considerably reduced speed; there being a double speed reduction by reason of the use of two complete planetary sets of gearing, in series relationship, but with a single outer gear I! serving as the orbit gear for both sets of planet pinions-the higher speed set of planets including the planet l8 and two additional planets (not shown) and the lower speed set including the planet 3| and two additional planets (not shown). The planet pinions 3I are mounted on shafts 32 which extend into, and therefore cause corresponding rotation of, the aforesaid barrel I5. Planets [8 are mounted on similar solid cylindrical members which extend int-c, and therefore cause corresponding rotation of planet race I! surrounding sleeve hearing I 3 and having a centrally extending toothed portion constituting a sun gear adapted to mesh and drive the planets M.

A multiple disk clutch 40 includes disks splined to the inner surface of barrel IS, with the remainder being splined to the outer surface of an interiorly threaded nut 4|. Resilient means, such as a plurality of coil springs 42 and an adjusting nut 43, are provided for varying the pressure with which disks 40 are maintained in engagement, as in the Lansing patent above identified.

Mounted for rotary and longitudinal movement within nut 4| is a threaded shaft 44 which is longitudinally splined at its inner end to drivably engage a correspondingly splined, tubular and outwardly extending portion 38a of the jaw clutch member 38. According to former practice, the screw-shaft 44 would have a stopnut threaded to its rear surface, such as stopnut 45 of the Lansing patent above identified; but the present invention involves the concept of eliminating such a stop-nut, and reconstructing said screw-shaft in such manneras to render it capable of performing the identical function heretofore performed by the additional stop-nut. Specifically, I enlargethe diameter of the internally threaded part 48 of the shell or out ll sumciently to permit the splined part ll of screw-shaft 44 to pass through the right-hand end of the nut, and also pass beyond the internally threaded part 48 of said nut, into operative relationship with the splines Ila on engine engaging clutch element 38. (Heretofore, the parts had to be assembled in the opposite direction, because of the smaller internal thread d1- ameter that prevented assembly from the right). In addition to enlarging the diameter of the threads 46 and 48 of the nut 4i and screw 44, respectively, I also cut a groove d9 around the screw, and I begin from a blank having a di ameter, at its right-hand end, that is consider ably greater than the diameter of the finished threads 46 and 48. This permits formation of a head portion 60 extending from groove 89 to the end surface which head portion serves as'a stop limiting movement of the screw precisely as does the separate stop-nut 35 of the Lansing patent, but without resort to use of such an additional member. Moreover, since the stophead 50 is integral with the screw-shaft, there is greater capacity to resist end thrust than in the former type of motion translating mechanism.

When the motor is energized by closing the circuit thereto from a suitable source of power, rotationoi the armature shaft is transmitted through the three-stage reduction gearing illustrated; to barrel' I 5. Rotation of the latter is yieldingly transmitted through clutch disks 40 to nut 4|.

Shaft 44 and jaw clutch member 38 tend to rotate in unison with nut 4|, but the rotation of these two members is resisted by resilient metallic ring 5! which causes non-metallic brake element 58 to have frictional engagement with the hub of member 38. The resultant drag on clutch member 38 is efl'ective to cause shaft 44 to move to the left, as viewed in Fig. 1, compressing spring 53 and yieldingly moving jaw member 38 into full meshing engagement with the corresponding engine member 39. When the jaw clutch members are in complete meshing engagement stop-head 50 abuts against the end surfaces 52 (see Figs. 5 and 6) of the threads 46 of nut M. Engine member 39, clutch member 38, and shaft 44 now rotate in unison with nut ii. The movement of member 38 is efie-ctive (through nut 6|) to move rod 59 to the left, relative to barrel I5. Spring 53 insures full engagement of the jaw clutch members.

age to the parts will result and the engine can never drive the motor armature due to the construction and arrangement of the Jaw clutch members. In the event the engine backfires, the disk clutch will yield and no damage to the parts will result.

The law clutch members 38 and 39 are normally disengaged, and energy is stored in the motor armature during the time interval consumed by the establishment of the driving connection. The inertia (momentum) thus acquired renders the cranking operation more certain, and

' decreases the drain of current on the battery or The electric motor is now efi'ective to crank the engine, and the inertia of the parts 01? the latter is gradually overcome. Relative rotation between barrel I5 and jaw member 38 is penmitted by the disk clutch 48 during the time in which the engine crankshaft is being brought up other source of power. The friction clutch permits the use of relatively light gears, protects the apparatus against backfire, and permits the engine crankshaft to be brought up to speed grad-. daily without a substantial decrease in the speed] of the motor armature.

This application is a division of my copending! application No. 362,272, filed October 22, 1940.

What is claimed is: a

l. A multiple planetary gearing for an engine starter of the like, said gearing including an orbit gear, a plurality of gears in mesh with said, orbit gear near one end thereoi, a second plurality of gea'rs in mesh with said orbit gear near the opposite end thereof, means for supporting said gears for planetary movement, said supporting means consisting of plane-surfaced planet carriers mounted on a common rotatable bearing, and of solid coaxially aligned cylindrical members of uniform diameter throughout,and having their ends disposed entirely within the end surfaces of the gears, on the. one end, and entirely within the end surfaces of the planet carriers, on the other, and means integral with one of said plane-suriaced planet carriers to transmit rotation from one of said plurality of gears to the other, said last-named planet carrier constituting the sole member occupying space between said two pluralities of gears, and also constituting the sole retaining means for certain'of saio". solid cylindrical members, the other of which solid cylindrical members act as abutments to assure correct positioning of the first-named solid cylindrical members.

2. Gearing including an orbit gear, a plurality of planet gears in mesh with said orbit gear, and means for supporting said planet gears for planetary movement, said supporting means in. cluding a rotatable bearing, a plane-surfaced planet carrier mounted on said bearing, and solid cylindrical members 01' uniform diameter completely filling registering holes in said planet gears and carrier and abutting, one against the other, to assure correct positioning in said registering holes.

ROMEO M. NARDONE. 

